Phase Behavior of Amphiphilic Molecules in the Presence of One Solvent: a Dissipative Particle Dynamics Study
Resource
Macromolecular Theory and Simulations,16(1),77-85.
Journal
Macromolecular Theory and Simulations
Pages
77-85
Date Issued
2007-01
Date
2007-01
Author(s)
Abstract
We simulate the phase behavior of amphiphilic molecules in the presence of one solvent by DPD. In general, DPD has successfully captured most of the effects of composition of amphiphilic molecules, solvent selectivity, and solvent amount, on the phase transition behavior obtained by both SCMF calculations and experiments. When a neutral good solvent is added, the solutions undergo a lyotropic transition analogous to the thermotropic transition in the melts. Furthermore, the order-disorder transition results obtained via DPD are in good agreement with theoretical predictions by including the fluctuation effects, as well as with experiments. In the selective solvents, various transitions from the "normal" phases (i.e., the minority blocks form the minor domains) to even the "inverted" phases (formed by the majority blocks) have been observed by varying solvent selectivity and solvent amount. Since the packing order of the spheres is greatly affected by the finite size of the simulation box, it becomes difficult to examine the most stable packing array of spheres via DPD as has been predicted by SCMF theory. However, DPD reveals a possible spherical order of A15, which has been ignored in current SCMF work but observed in some amphiphilic molecule systems. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.